Question: $\overline{AC}$ is $8$ units long $\overline{BC}$ is $4$ units long $\overline{AB}$ is $4\sqrt{5}$ units long What is $\cos(\angle ABC)$ ? $A$ $C$ $B$ $8$ $4$ $4\sqrt{5}$
Solution: SOH CAH TOA os = djacent over ypotenuse adjacent $= \overline{BC} = 4$ hypotenuse $= \overline{AB} = 4\sqrt{5}$ $\cos(\angle ABC )=\frac{4}{4\sqrt{5}}$ $=\dfrac{ \sqrt{5}}{5}$